Diagnosis of Cardiovascular Disease Significantly
Increases Risk of Hip Fracture
Twin of cardiovascular diseased sibling also
experiences increased rate of hip fracture
Oct. 20, 2009 - A study that includes twins finds
that the risk of hip fracture was significantly increased following a
diagnosis of cardiovascular disease (CVD), with analysis also suggesting
a genetic predisposition to the development of CVD and, according to a
study in the October 21 issue of the Journal of the American Medical
Association (JAMA).
CVD and osteoporosis, which are common in elderly
individuals, have been regarded as independent age-related disorders.
Research has suggested that there may be common mechanisms that cause
these diseases.
Stroke is a well-documented risk factor for hip
fracture, but there has been uncertainty concerning whether other CVDs
may increase the risk of future hip fracture, according to background
information in the article.
"It is also unknown whether the risk for hip
fracture differs depending on CVD diagnosis and sex, as well as whether
the risk reflects lifestyle and individual environmental influences or
genetic constitution," the authors write.
Information from 31,936 twins in the Swedish Twin
Registry was used to investigate the association between cardiovascular
events and future hip fracture risk and to examine to what extent the
relation was attributable to genes or associated with other lifestyle
factors.
The researchers, Ulf Sennerby, M.D., of Uppsala
University, Uppsala, Sweden, and colleagues, note that a study that
includes twins provides a framework for an ordinary group analysis while
simultaneously examining whether the relation between cardiovascular
events and hip fracture is explained by genetic and early environmental
factors.
The twins, born from 1914-1944, were followed up
from the age of 50 years. The National Patient Registry identified twins
with CVD and fractures from 1964 through 2005.
The researchers found that the crude absolute rate
of hip fractures was highest after a diagnosis of heart failure or
stroke, compared to those after a diagnosis of peripheral
atherosclerosis or ischemic heart disease and lowest for those without a
CVD diagnosis.
In comparison with individuals without CVD,
patients with heart failure had about a 4-fold increased rate of hip
fracture and individuals with a stroke had 5 times the risk. The
elevated hip fracture rate was also present after ischemic stroke,
hemorrhagic stroke, peripheral atherosclerosis and ischemic heart
disease.
"Identical twins without heart failure and stroke
also had, after their co-twins had been exposed to these respective
diseases, an increased rate of hip fracture," the authors write.
These sibling twins who were considered to be "pseudoexposed"
(i.e., the twin without CVD was considered to be "pseudoexposed" to
having CVD based on their co-twin having a CVD event) for heart failure
had a 3.7-fold increased risk for hip fracture; pseudoexposure for
stroke had a 2.3 times higher risk of hip fracture.
"An increased hip fracture risk for the
pseudoexposure in the co-twin analyses, particularly in identical twins,
is an indication that genes predispose to the development of CVD and
fractures.
Most of the overall increased rate of hip fracture
after heart failure (and part of the increased risk after stroke)
appears to be explained by genes or by early environmental sharing
(i.e., not individual lifestyle habits or other individual-specific
environmental factors)," the researchers write.
"Clinicians should be aware of the considerably
increased rate of hip fracture in both sexes, especially after a recent
hospitalization for CVD. Genetic predisposition is probably a major
determinant of the excess fracture rate," the authors conclude.
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Oct. 20, 2009 - A study that includes twins finds
that the risk of hip fracture was significantly increased following a
diagnosis of cardiovascular disease (CVD), with analysis also suggesting
a genetic predisposition to the development of CVD and, according to a
study in the October 21 issue of the Journal of the American Medical
Association (JAMA).